<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    .user {
        display: flex;
        flex-wrap: wrap;
    }
    
    .user input {
        width: 100%;
        /* flex: 1; */
    }
    
    .rule {
        display: flex;
    }
</style>

<body>
    <div class="user">
        <input type="text">
        <input type="text">
        <input type="text">
    </div>
    <div class="rule">
        <div><input type="checkbox" name="" id="check"></div>
        <div>
            同意
            <a href="#">服务条款</a>
            <a href="#">隐私政策</a>
            <a href="#">儿童隐私政策</a>
        </div>


    </div>
</body>

</html>